With the rapid increase in the volume of data consumption on mobile devices, the need for high bandwidth, compact, and power conserving signal conditioning circuits is growing. To support the high data volumes, signal conditioning circuits must satisfy stringent performance specifications, such as fast setup when exiting power down modes, low jitter, and low standby bias current. The rapidly growing throughput speeds for various I/O (input/output) standards is causing signal conditioning circuit design specifications to become more demanding and complicated.
The signal conditioning performed by a repeater is a critical task in serial communication systems. Repeaters are used in a wide range of applications, including redrivers and retimers. One objective of repeaters is to regenerate signals to boost the signal quality of high-speed interfaces. Repeaters are a key technology for addressing the signal integrity challenges that higher data rates introduce across every industry and serial data protocol.
Repeaters with power management often provide multiple standby states. Each standby state corresponds to a different amount of standby current consumption, such as for different biasing conditions. Typically, the lower the standby current, the longer it takes to transition to a signal transmission state. For example, the standby state with the highest current (i.e., the least power savings) may have a transition time in the range of microseconds, while the standby state with the lowest current (i.e., the most power savings) may be in the range of milliseconds.
Certain serial data protocols constrain the transition time from standby to transmitting low frequency signals used for sideband communications. In certain scenarios, a repeater may enter the standby states with greater power savings less often because of the need to comply with a transition time requirement.